Holographic film with first and second translucent photosensitive recording layers

Abstract

Various holographic films for recording multicolor volume holograms, especially full color volume reflection holograms, and to manufacturing techniques for such film, and to corresponding methods of recording multicolor and full-color volume, in particular volume reflection holograms. We describe a holographic film for recording a multicolor volume hologram, the film including: a carrier; a first photosensitive recording layer sensitive to one or both of red and green laser light; and a second photosensitive recording layer sensitive to blue laser light. Both the first and second photosensitive recording layers include silver halide and have a grain size of less than 30 nm, and at least one of the photosensitive recording layers has a thickness of greater than 3 μm and less than 5 μm.

What is claimed is: 
     
       1. A holographic film for recording a multicolor volume hologram, the film comprising:
 a carrier; 
 a first photosensitive recording layer sensitive to one or both of red and green laser light; and 
 a second photosensitive recording layer sensitive to blue laser light, wherein the first and second photosensitive recording layers each are translucent to said blue laser light and said one or both of red and green laser light to allow fringe structures defined by phase modulation to be recorded independently in said first and second photosensitive recording layers. 
 
     
     
       2. A holographic film as claimed in  claim 1  wherein both said first and said second photosensitive recording layers comprise photopolymer recording material. 
     
     
       3. A holographic film as claimed in  claim 1  wherein both said first and said second photosensitive recording layers comprise silver halide and have a grain size of less than 30 nm, and wherein at least one of said first and second photosensitive recording layers has a thickness of greater than 3 μm and less than 5 μm. 
     
     
       4. A holographic film as claimed in  claim 1  wherein both said first and said second photosensitive recording layers comprise silver halide and have a grain size of less than 30 nm. 
     
     
       5. A holographic film as claimed in  claim 1  wherein one or both of said first and second photosensitive recording layers has a thickness of less than 5 μm. 
     
     
       6. A holographic film as claimed in  claim 1  wherein said first and second photosensitive recording layers are transparent to said blue laser light and said one or both of red and green laser light. 
     
     
       7. A method of recording a multicolour image into a volume hologram in a holographic film, the method comprising:
 providing a carrier; 
 providing a first photosensitive recording layer sensitive to one or both of red and green laser light; 
 providing a second photosensitive recording layer sensitive to blue laser light; 
 wherein the first and second photosensitive recording layers each are translucent or transparent to said blue laser light and said one or both of red and green laser light to allow fringe structures defined by phase modulation to be recorded independently in said first and second photosensitive recording layers; and 
 recording a first fringe structure defined by phase modulation in said first photosensitive recording layer using one or both of said red and green laser light; and 
 recording a second fringe structure defined by phase modulation in said second photosensitive recording layer using said blue laser light; 
 wherein the colour components of said multicolour image are recorded simultaneously by simultaneously illuminating the film with said blue laser light and said one or both of said red and green laser light. 
 
     
     
       8. A method of manufacturing the holographic film for recording a multicolor volume hologram, the method comprising:
 providing a carrier; 
 depositing onto said carrier a first photosensitive recording layer sensitive to one or both of red and green laser light; and 
 depositing onto said carrier a second photosensitive recording layer sensitive to blue laser light; 
 wherein the first and second photosensitive recording layers each are translucent or transparent to said blue laser light and said one or both of red and green laser light to allow fringe structures defined by phase modulation to be recorded independently in said first and second photosensitive recording layers.